Ibandronate Sodium is a third-generation nitrogen-containing bisphosphonate characterized by an aliphatic tertiary amine side chain.
Ibandronate Sodium is a white crystalline powder. The free acid has MW 319.23 (CAS No.: 114084-78-5). The monosodium salt (anhydrous) of the acid has MW 341.23 (CAS No.: 138844-81-2). The monosodium salt monohydrate has MW 359.23 (CAS No.: 138926-19-9).

The preparation of ibandronic acid monosodium salt is described in, for example, U.S. Pat. No. 4,927,814. The '814 patent describes the following schemes:

The preparation of ibandronic acid is taught in U.S. Pat. No. 4,927,814, wherein an ion-exchange chromatography is used in work-up. The present inventors repeated the procedure described in the '814 patent. No solid material was obtained, but an oily precipitate was the crude product. The skilled artisan knows that solids are easier to manipulate than oils. Clearly there is a need for a method of making a solid ibandronic acid.
The monosodium salt of ibandronic acid is marketed under the trade name Boniva®. Boniva® was developed by Hoffmann-La Roche for the treatment of bone disorders such as: hypercalcaemia of malignancy, osteolysis, Paget's disease, osteoporosis and metastatic bone disease. Boniva® is also marketed in Europe under the name Bondronat for cancer-related bone complications. Bondronat is available in ampoule with 1 ml concentrate for solution for infusion contains 1.125 mg of Ibandronic acid monosodium salt monohydrate, corresponding to 1 mg of ibandronic acid.
Ibandronic acid can be used as an intermediate in the process for the preparation of Ibandronate sodium.
The discovery of new polymorphic forms of a pharmaceutically useful compound provides a new opportunity to improve the performance characteristics of a pharmaceutical product. It enlarges the repertoire of materials that a formulation scientist has available for designing, for example, a pharmaceutical dosage form of a drug with a targeted release profile or other desired characteristic. There is a need in the art for polymorphic forms of ibandronic acid.